Rachel McAdams in Marchesa | “Sherlock Holmes: A Game Of Shadows” Premiere

Last night was the premiere of Warner Bros. Pictures’ “Sherlock Holmes: A Game Of Shadows”, but it was no mystery that Rachel McAdams looked downright incredible when she arrived at the Regency Village Theatre in Westwood, California in a remarkable silver metallic gown by Marchesa.

The 33-year-old blonde beauty was radiant in the Resort 2012 floor-length dress that featured a wide neckline and long-sleeves; perhaps the jaw-dropping moment was when onlookers got a view of the super low cut-out back and draping detail — and let’s not forget that dramatic train!

A sexy draped back and and flowing train added insta-drama for McAdams' premiere look.

Rachel made her presence known with this show stopper of a look.

Her short curly coif was multi-twisted into a glorious pulled up style that gave her some volume in the front.